I've checked our records and haven't seen any investigations similar to yours, Gbgovols-4life.
First, let's check what happened to these transactions. Let's pull up the Audit log report. From there, we'll know if these transactions were deleted. Here's how:
If invoices are deleted accidentally, you'll have to enter them manually. Or, if you have the QuickBooks Online Advanced version, you can import them. Concerning the contact list, you can also import them.
However, if it wasn't deleted, you're probably experiencing browser issues. Let's perform some basic troubleshooting. We'll start by opening QuickBooks Online through an incognito window. It's the best place to isolate browser hiccups. Here are the shortcut keys:
If you're able to see the invoices and contact list, go back to your regular browser, then clear the cache to refresh the account. We advise our customers to delete them now and then to prevent issues like this.
On the other hand, you can use a different browser to help us narrow the cause of this behavior.
You can get back to this thread if you need more help. We'll reply to you as soon as we can.